1. Technical Field
The present disclosure relates to a semiconductor memory device, and more particularly, to a nonvolatile semiconductor memory device.
2. Related Art
A semiconductor memory device can be manufactured with semiconductor materials such as silicon (Si), germanium (Ge), gallium arsenide (GaAs) and indium phosphide (InP). Semiconductor memory devices can be divided into volatile memory devices and nonvolatile memory devices.
The volatile memory device is a memory device in which stored data are erased when a power source is shut off. The volatile memory device includes Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM) and Synchronous Dynamic Random Access Memory (SDRAM). The nonvolatile memory device is a memory device that retains stored data even when a power source is shut off. The nonvolatile memory device includes Read-Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Electrical Erasable Programmable Read Only Memory (EEPROM), flash memory device, Phase-change Random Access Memory (PRAM), Magnetoresistive Random Access Memory (MRAM), Resistive Random Access Memory (RRAM) and Ferroelectric Random Access Memory (FRAM). The flash memory device is largely categorized into a NOR type and a NAND type.